The goalkeeper was acquired by Inter Miami from the San Jose Earthquakes in a trade in November 2019. 

He is a former NCAA Division I soccer player at the University of California, Berkeley. He played at the school for four years, making 54 appearances and keeping 16 clean sheets. The goalkeeper made a career-high nine saves on two separate occasions, once as a freshman against Oregon State University and once as a sophomore against the University of Portland. 

Callender was named to the United Soccer Coaches NCAA All-Far West Region First Team and the All-Pac-12 First Team for the 2017 season. For the 2018 season, he was named to the preseason MAC Hermann Trophy Watch List and earned United Soccer Coaches NCAA All-Far West Region Third Team and All-Pac-12 Second Team honors.  

The 6-foot-3 goalkeeper was invited to the U.S. U-23 Men’s National Team training camp in September. The training camp is part of the U.S.’s campaign to qualify for the 2020 Olympics in Tokyo.